At the harbour of Faros, you can see the typical flat stone, called schist, which is used as building stone in Sifnos and also as a stone to pave the kilometers of ancient walking paths of Sifnos. The word schist is derived from the Greek word meaning "to split", which is a reference to the ease with which schists can be split along the plane in which the platy minerals lie. Although the layers were flat when they were deposited, you can see here clearly the effect of the tectonic pressure on the rocks of the island. Schist is a medium-grade metamorphic rock. The shining effect is not silver or any other metal but is cause by the mica flakes.